Importance of dissolved organic nitrogen in the north Atlantic Ocean in sustaining primary production: a 3-D modelling approach

Charria, Guillaume; Dadou, Isabelle; Llido, J.; Drévillon, Marie; Garçon, Véronique

doi:10.5194/bg-5-1437-2008

Cited by 19 publications

(16 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Assigning equations and parameter values for DOM cycling is fraught with difficulty given our limited understanding of interactions within microbial communities and of 384 A. Yool et al: A description of MEDUSA-1.0 the physiology of heterotrophic bacteria (Christian and Anderson, 2002). Few estimates are available for the kinetic parameters defining the degradation of DOM in marine systems, particularly the semi-labile fraction, and it is therefore questionable how reliably it is possible to simulate this process in models (Christian and Anderson, 2002).…”

Section: State Variablesmentioning

confidence: 99%

“…Yool et al: A description of MEDUSA-1.0 the physiology of heterotrophic bacteria (Christian and Anderson, 2002). Few estimates are available for the kinetic parameters defining the degradation of DOM in marine systems, particularly the semi-labile fraction, and it is therefore questionable how reliably it is possible to simulate this process in models (Christian and Anderson, 2002). Parameter estimates for DOM cycling are highly variable in models and require further validation.…”

Section: State Variablesmentioning

confidence: 99%

See 1 more Smart Citation

Medusa-1.0: a new intermediate complexity plankton ecosystem model for the global domain

2011

View full text Add to dashboard Cite

Abstract. The ongoing, anthropogenically-driven changes to the global ocean are expected to have significant consequences for plankton ecosystems in the future. Because of the role that plankton play in the ocean's "biological pump", changes in abundance, distribution and productivity will likely have additional consequences for the wider carbon cycle. Just as in the terrestrial biosphere, marine ecosystems exhibit marked diversity in species and functional types of organisms. Predicting potential change in plankton ecosystems therefore requires the use of models that are suited to this diversity, but whose parameterisation also permits robust and realistic functional behaviour. In the past decade, advances in model sophistication have attempted to address diversity, but have been criticised for doing so inaccurately or ahead of a requisite understanding of underlying processes. Here we introduce MEDUSA-1.0 (Model of Ecosystem Dynamics, nutrient Utilisation, Sequestration and Acidification), a new "intermediate complexity" plankton ecosystem model that expands on traditional nutrient-phytoplankton-zooplanktondetritus (NPZD) models, and remains amenable to globalscale evaluation. MEDUSA-1.0 includes the biogeochemical cycles of nitrogen, silicon and iron, broadly structured into "small" and "large" plankton size classes, of which the "large" phytoplankton class is representative of a key phytoplankton group, the diatoms. A full description of MEDUSA-1.0's state variables, differential equations, functional forms and parameter values is included, with particular attention focused on the submodel describing the export of organic carbon from the surface to the deep ocean. MEDUSA-1.0 is used here in a multi-decadal hindcast simulation, and its biogeochemical performance evaluated at the global scale.

show abstract

Section: State Variablesmentioning

confidence: 99%

Section: State Variablesmentioning

confidence: 99%

Medusa-1.0: a new intermediate complexity plankton ecosystem model for the global domain

2011

View full text Add to dashboard Cite

show abstract

“…Kristiansen et al, 1994) and dDON (e.g. Charria et al, 2008) is imposed at each grid cell. Boundary conditions at the North Atlantic and North Pacific sectors are data from the World Ocean Atlas 2005 (NODC, 2006) for NO 3 , and null for the remaining nine biogeochemical tracers.…”

Section: The Biogeochemical Modelmentioning

confidence: 99%

Modelling the impact of riverine DON removal by marine bacterioplankton on primary production in the Arctic Ocean

et al. 2015

View full text Add to dashboard Cite

Abstract. The planktonic and biogeochemical dynamics of the Arctic shelves exhibit a strong variability in response to Arctic warming. In this study, we employ a biogeochemical model coupled to a pan-Arctic ocean-sea ice model (MITgcm) to elucidate the processes regulating the primary production (PP) of phytoplankton, bacterioplankton (BP), and their interactions. The model explicitly simulates and quantifies the contribution of usable dissolved organic nitrogen (DON) drained by the major circum-Arctic rivers to PP and BP in a scenario of melting sea ice (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011). Model simulations suggest that, on average between 1998 and 2011, the removal of usable riverine dissolved organic nitrogen (RDON) by bacterioplankton is responsible for a ∼ 26 % increase in the annual BP for the whole Arctic Ocean. With respect to total PP, the model simulates an increase of ∼ 8 % on an annual basis and of ∼ 18 % in summer. Recycled ammonium is responsible for the PP increase. The recycling of RDON by bacterioplankton promotes higher BP and PP, but there is no significant temporal trend in the BP : PP ratio within the ice-free shelves over the 1998-2011 period. This suggests no significant evolution in the balance between autotrophy and heterotrophy in the last decade, with a constant annual flux of RDON into the coastal ocean, although changes in RDON supply and further reduction in sea-ice cover could potentially alter this delicate balance.

show abstract

“…[3] Prior efforts to quantify the sustenance of upper ocean productivity by DON have focused on the Atlantic Ocean where the greatest density of DON observations exists and a clear east-to-west gradient in DON concentration has been observed (>5 mmol kg -1 in the east to~4.5 mmol kg -1 in the west) [Mahaffey et al, 2004;Roussenov et al, 2006;Charria et al, 2008;Torres-Valdés et al, 2009]. These studies have considered the allochthonous input of semilabile DON (lifetime of months to years), generated at the productive gyre margins, to the subtropical gyre interior and its potential role as an organic nutrient for enhancing export production there.…”

Section: Introductionmentioning

confidence: 99%

Dissolved organic nitrogen in the global surface ocean: Distribution and fate

Letscher

Hansell

Carlson

et al. 2013

Global Biogeochemical Cycles

122

View full text Add to dashboard Cite

The allochthonous supply of dissolved organic nitrogen (DON) from gyre margins into the interior of the ocean's oligotrophic subtropical gyres potentially provides an important source of new N to gyre surface waters, thus sustaining export production. This process requires that a fraction of the transported DON be available to euphotic zone photoautotroph communities via mineralization. In this study, we investigated the biological and physical controls on the distribution and fate of DON within global ocean surface waters. Inputs of nitrate to the euphotic zone at upwelling zones fuel net accumulation of a DON pool that appears to resist rapid microbial remineralization, allowing subsequent advective transport into the subtropical gyres. Zonal gradients in DON concentrations across these gyres imply a DON sink in the surface layer. Assessment of the physical dynamics of gyre circulation and winter mixing revealed a pathway for DON removal from the mixed layer via vertical transport to the deep euphotic zone, which establishes the observed zonal gradients. Incubation experiments from the Florida Straits indicated surface‐accumulated DON was largely resistant (over a few months) to utilization by the extant surface bacterioplankton community. In contrast, this same material was remineralized three times more rapidly when exposed to upper mesopelagic bacterioplankton. These results suggest the primary fate of surface DON to be removal via vertical mixing and subsequent mineralization below the mixed layer, implying a limited role for direct DON support of gyre export production from the surface layer. DON may contribute to export production at the eastern edges of the subtropical gyres, but only after its mineralization within the deep euphotic zone.

show abstract

Importance of dissolved organic nitrogen in the north Atlantic Ocean in sustaining primary production: a 3-D modelling approach

Cited by 19 publications

References 45 publications

Medusa-1.0: a new intermediate complexity plankton ecosystem model for the global domain

Medusa-1.0: a new intermediate complexity plankton ecosystem model for the global domain

Modelling the impact of riverine DON removal by marine bacterioplankton on primary production in the Arctic Ocean

Dissolved organic nitrogen in the global surface ocean: Distribution and fate

Contact Info

Product

Resources

About